My new Shimano brake cable casing did not fit with my old Shimano brake levers. This is fair, as my bike is an old retro model that's probably 30 years old. To adapt to the modern bikes and keep this beautiful old bike going, I designed and printed this adaptor to properly seat the old brake cable housing to my old brake levers. It fits great, and it has been tested on a 1600 km cross-europe bikeride without problems. 

The design is very simple. It is intended to be printed in the upward position, and it will need supports. I printed in ASA because of the UV and heat resistance, but PETG or other alternatives would certainly also be fine.

The exact dimensions are shown in the included sketch. If this does not fit your case, feel free to use my CAD drawing on OnShape to create something that fits you. If you are not comfortable modifying a CAD model yourself, you are also welcome just to ask me and can create other sizes for you.

CAD link: Onshape model here

Enjoy!